1. Field of the Invention
The invention relates to a radio network communication system in which a radio communication terminal such as a cellular phone, and more particularly to such a radio network communication system suitable for transmitting a larger amount of data to a plurality of radio communication terminals.
2. Description of the Related Art
There is widely used a handy radio communication terminal such as a personal digital cellular (PDC), a personal handy phone system (PHS) or a handy communication terminal including a radio modem. Among such handy radio communication terminals, a cellular phone such as PDC or PHS has been first used as a small-sized telephone. However, as multi-media communication has developed, they are used also in a field of data communication, for instance, they are used for transmitting and receiving electronic mails.
In particular, an internet is frequently used in a lot of homes as well as in a lot of offices, resulting in a remarkable increase in an access by a user of a radio communication terminal to a world wide web (WWW) from a place remote from an office and a home. Accordingly, a handy radio communication terminal is, now designed to include a software for making access to a World Wide Web, ensuring that a user can make access to and observer a desired homepage.
A homepage is made of a content which is called a hypertext. A hypertext is designed to allow a text, a still picture, a moving picture and voices in a hypertext to link to an object including associated data. Hence, selecting a certain word in a hypertext, which links to other data, it would be possible to retrieve and display data associated with the word.
As a hypertext, there are a hypercard, a hypertext markup language (HTML), and so on.
A presently available radio communication terminal has a quite low communication rate in comparison with an access rate at which an access is made to a homepage through a telephone network or CATV (cable television). Hence, there has been suggested a radio network communication system which allows a handy radio communication terminal to readily download a hypertext including pages having a still picture, a moving picture and/or voices.
For instance, Japanese Unexamined Patent Publication No. 10-171702 has suggested a communication terminal which enhances a response rate at which a page is switched to a next page while the terminal is making access to a homepage.
In the suggested communication terminal, names of a server and a directory in a presently displayed page are identified, and then, an associated HTML file located at a lower layer is retrieved in series, based on the identified names. Then, the thus retrieved HTML file is stored in a memory. When a homepage reader turns a page, a HTML file associated with the next page is read out of the memory, and the thus read-out HTML file is displayed at a display unit. As a result, a response rate for displaying a HTML file can be enhanced.
In the above-mentioned Japanese Unexamined Patent Publication No. 10-171702, HTML files are retrieved in series, and then, stored in a memory. Accordingly, it is necessary to store pages having a small possibility to be displayed, in a memory, in order to swiftly display a requisite page. Hence, the communication terminal suggested in the Publication is suitable for a relatively large-sized communication terminal including a memory having a sufficient capacity, and having a sufficient communication rate.
However, the communication terminal is accompanied with a problem that the communication terminal has to download data which will not be used.
To solve this problem, Japanese Unexamined Patent Publication No. 11-212889 has suggested a communication terminal which reduces not only a load of displaying data, but also a load of downloading data.
FIG. 1 is a block diagram of the suggested communication terminal.
The communication terminal 100 is comprised of a reader 102 to which a communication line 101 is connected, a memory 103, a hypertext analyzer 104 including an image file reader 106, an image developer 107, a layout designer 108, and a display unit 109.
The reader 102 reads out a hypertext transmitted through the communication line 101. The thus read-out hypertext is stored in the memory 103. The hypertext analyzer 104 analyzes the hypertext stored in the memory 103, and reads out data by which an image file is defined, stored in the hypertext. Then, the hypertext analyzer 104 determines whether the image file is read out from a server (not illustrated).
When the image file is to be read out, the image file reader 106 does so, and the image developer 107 develops the thus read-out image file. The layout designer 108 designs a layout, based on the data analyzed by the hypertext analyzer 104. The display unit 109 displays data formed based on the layout designed by the layout designer 108.
The hypertext analyzer 104 determines whether the image file is read out from a server, in accordance with whether a file of the image data to be read out is greater in a size than a threshold size. When the image file is not to be read out, an eye-con is displayed in place of the image file at a place where the image file was to be displayed.
Japanese Unexamined Patent Publication No. 11-212889 has made suggestions other than the communication terminal illustrated in FIG. 1. For instance, whether an image file is to be read out is determined in accordance with presence or absence of a link as well as a size of an image file. As an alternative, whether an image file is to be read out is determined, based on a capacity at which a display unit of a receiver terminal displays data.
In the communication terminal illustrated in FIG. 1, a load of the communication terminal 100 is reduced in accordance with a status of the communication terminal 100 acting as a data receiver, ensuring that received data can be effectively displayed.
In a radio network communication. system in which a radio communication terminal such as the communication terminal 100 is used, a load of a communication network as well as a load of a radio communication terminal has to be considered.
For instance, in a cellular phone system, base stations are positioned to cover a relatively small area in order to effectively utilize a limited number of frequencies. Frequencies are assigned to cellular phones such that frequencies are not interfered with each other in adjacent areas, and those frequencies are repeatedly used.
In addition, a frequency is divided into a plurality of frequencies by time division to use in a plurality of channels. In general, if a channel is defined for a frequency band, it would be possible to increase an amount of data transmittable per a unit time. However, it would be unavoidable that the number of channels is reduced accordingly, and hence, the number of users per a unit area is unavoidably reduced.
As a result, there exists an optimal number of communication terminals which can be connected to a, channel or which can concurrently make radio communication, in a radio network communication system in which a radio communication terminal such as PDC, PHS, or a handy communication device including a radio modem is used. Hence, if the system illustrated in FIG. 1, which is supposed to be used as a non-radio communication system, is applied to a radio network communication system, though respective communication terminals might operate well, the radio network communication system does not operate well, or some communication terminals might not be able to operate.
That is, even if a communication terminal to which a homepage is downloaded had a high capacity for displaying data, or could process images at a high rate, the communication terminal may occupy network resources more than necessary, resulting in that other communication terminals cannot make radio communication well.
In view of the above-mentioned problems in the prior art, it is an object of the present invention to provide a radio network communication system which is capable of enhancing a communication efficiency not only in a communication terminal but also in a base station making radio communication with communication terminals.
In one aspect of the present invention, there is provided a radio network communication system including (a) at least one server storing files therein, (b) at least one client terminal making a request to download a desired file thereto among the files stored in the server, and (c) at least one base station including (c1) a data transceiver which makes radio-communication with the client terminal to receive data from and transmit data to the client terminal, and which, when the request is made by the client terminal, transmits the request to the server and receives all data constituting the desired file, from the server, and (c2) a load measurement unit which measures a network load between the client terminal and the base station, the base station dividing the received file into sub-files in accordance with the load measured by the load measurement unit, and transmitting each of the sub-files to the client terminal.
In the above-mentioned radio network communication system, the base station is designed to include a load measurement unit for measuring a load between the client terminal and the base station. A file which the client terminal requests to download thereto is first stored in the base station, and the base station divides the file into sub-files and transmits the sub-file or sub-files to the client terminal in accordance with a load measured by the load measurement unit.
Accordingly, the above-mentioned radio network communication system can solve the problem that a certain client terminal occupies a channel.
Furthermore, when a client terminal requests the same file to download thereto again, since the base station has already stored the file therein, the base station can transmit the requested file to the client terminal without requesting the server to transmit the file to the base station.
Since the base station transmits the divided files or sub-files to the client terminal, if the client terminal checks a first transmitted sub-file and determines that the rest of sub-files are not necessary to be transmitted thereto, it is not necessary to download the entire file. This ensures that a load on a network can be reduced in comparison with the conventional radio network communication system in which a file was downloaded in its entirety to a client terminal.
There is further provided a radio network communication system including (a) at least one server storing therein files each constituting a homepage, the files being stored in association with a uniform resource locator (URL) indicating a site of the homepage in an internet, (b) at least one client terminal making a request to download a desired file thereto among the files stored in the server, by indicating a uniform resource locator of the desired file, and (c) at least one base station including (c1) a data transceiver which makes radio-communication with the client terminal to receive data from and transmit data to the client terminal, and which, when the request is made by the client terminal, transmits the request to the server and receives all data constituting the desired file, from the server, and (c2) a load measurement unit which measures a network load between the client terminal and the base station, the base station dividing the received file into sub-files in accordance with the load measured by the load measurement unit, and transmitting each of the sub-files to the client terminal.
In the above-mentioned radio network communication system, the base station is designed to include a load measurement unit for measuring a load between the client terminal and the base station. A file corresponding to URL of a homepage which the client terminal requests to download thereto is first stored in the base station, and the base station divides the file into sub-files and transmits the sub-file or sub-files to the client terminal in accordance with a load measured by the load measurement unit.
Accordingly, the above-mentioned radio network communication system can solve the problem that a certain client terminal occupies a channel.
Furthermore, when a client terminal requests the same file to download thereto again, since the base station has already stored the file therein, the base station can transmit the requested file to the client terminal without requesting the server to transmit the file to the base station.
Since the base station transmits the divided files or sub-files to the client terminal, if the client terminal checks a first transmitted sub-file and determines that the rest of sub-files are not necessary to be transmitted thereto, it is not necessary to download the entire file. This is quite effective, taking into consideration that a user doing net-surfing frequently makes access to a second homepage before he/she finishes reading a first homepage.
It is preferable that the files are described in a descriptive language in which a homepage should be described, and that the base station further includes (c3) a database storing therein data about a range in which a display unit of the client terminal can display data at a time, (c4) a divider which divides the received file into sub-files in the unit of a page, and (c5) an editor which edits the sub-files such that a descriptive language in each of the sub-files properly forms a page.
In accordance with the above-mentioned radio network communication system, data is displayed in the client terminal by pages by means of the database storing therein data about a range in which a display unit of the client terminal can display data at a time. Hence, the client terminal can reduce data transmitted at a time from the base station, without feeling incompatibility in displaying data.
In addition, even if a file is described in HTML data, the editor edits respective pages, when the file is divided into pages, such that each of pages have indications indicative of a leading edge or a trailing edge. Hence, the client terminal can display the thus edited pages as they are.
Furthermore, when the client terminal requests the base station to transmit a new page thereto, since data about a presently displayed page is known, the client terminal can receive HTML data from the base station by indicating a desired page.
It is preferable that the base station further includes a transmitter which transmits the sub-files to the client terminal by pages applicable to a client terminal, in accordance with the network load measured by the load measurement unit.
The transmitter makes it possible for the base station to transmit data to a client terminal by every two or more pages, when a smaller load is exerted on a network than a load exerted on a network when data is transmitted by respective pages. This ensures more effective data transmission.
It is preferable that the base station transmits the received files to the client terminal at a time, when the network load measured by the load measurement unit is equal to or smaller than a threshold load.
When a load between a client terminal and a base station is quite small, for instance, when client terminals belonging to the same channel in the same base station do not concurrently make access to a homepage, data may be transmitted at a time from a base station to a client terminal, ensuring that a file can be downloaded optimally under certain conditions.
It is preferable that the client terminal includes (b1) a detector which detects a request to display new pages on a display unit, and (b2) a transmitter which transmits the request to the base station.
When the detector detects a request to display a new page or pages on a display unit of a client terminal, the transmitter transmits the request to a base station. In response, the base station transmits the requested data to the client terminal, which ensures that a load on a network can be dispersed.
There is still further provided a radio network communication system including (a) an internet network, (b) first to N-th servers each storing homepages therein and each being in communication with the internet network, wherein N is an integer equal to or greater than 2, (c) first to M-th base stations each being in communication with the internet network, wherein M is an integer equal to or greater than 2, each of the first to M-th base stations including a memory to store data received from the servers therein, (d) client terminals each of which is accessible to the internet network through one of the base stations, each of the first to M-th base stations, on receiving a request from one of the client terminals to download a desired homepage to the one of the client terminals, receiving data from the associated server, and storing the thus received data in the memory, each of the first to M-th base stations calculating a load between itself and the one of the client terminals, and transmitting the data to the one of the client terminals by pages in accordance with the load.
In another aspect of the present invention, there is provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) the client terminal making a request to download a desired file thereto among the files stored in the server, (b) the base station receiving all data constituting the desired file, from the server, (c) calculating a network load between the client terminal and the base station, (d) the base station dividing the received file into sub-files in accordance with the load calculated in the step (c), and (e) the base station transmitting each of the sub-files to the client terminal.
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) the client terminal making a request to download a desired file thereto among the files stored in the server, by indicating a uniform resource locator (URL) of the desired file, (b) the base station receiving all data constituting the desired file, from the server which stores files each constituting a homepage, the files being stored in association with a uniform resource locator (URL) indicating a site of the homepage in an internet, (c) calculating a network load between the client terminal and the base station, (d) the base station dividing the received file into sub-files in accordance with the load calculated in the step (c), and (e) the base station transmitting each of the sub-files to the client terminal.
It is preferable that the files are described in a descriptive language in which a homepage should be described, and that the method further includes the steps of the base station storing therein data about a range in which a display unit of the client terminal can display data at a time, the base station dividing the received file into sub-files in the unit of a page, and the base station editing the sub-files such that a descriptive language in each of the sub-files properly forms a page.
It is preferable that the method further includes the step of the base station transmitting the sub-files to the client terminal by pages applicable to a client terminal, in accordance with the network load calculated in the step (c).
It is preferable that the base station transmitting the received files to the client terminal at a time, when the network load is equal to or smaller than a threshold load.
It is preferable that the method further includes the step of the client terminal detecting a request to display new pages on a display unit, and transmitting the request to the base station.
There is still further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load between the base station and the client terminal, (e) calculating an amount of data transmittable to the client terminal, in accordance with the load, (f) comparing the data calculated in the step (e) to the data stored in the memory in the step (c), and (g) the base station transmitting the data to the client terminal, if an excessive load is not exerted on an internet network even if the data stored in the memory is transmitted to the client terminal at a time.
It is preferable that the method further includes the step of determining the number of pages transmittable to the client terminal at a time, the base station transmitting the pages to the client terminal in the step (g).
There is yet further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load between the base station and the client terminal, (e) calculating an amount of data transmittable to the client terminal, in accordance with the load, (f) comparing the data calculated in the step (e) to the data stored in the memory in the step (c), (g) the base station editing a first page in accordance with a capacity at which the client terminal can display data at a time on a display unit thereof, if the data stored in the memory in the step (c) is greater in an amount than the data calculated in the step (e), and (h) the base station transmitting the first page to the client terminal.
It is preferable that the method further includes the steps of (h) editing a second and later pages on receipt of a request from the client terminal, and (i) the base station transmitting the thus edited second or later pages to the client terminal.
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load between the base station and the client terminal, (e) calculating an amount of data transmittable to the client terminal, in accordance with the load, (f) comparing the data calculated in the step (e) to the data stored in the memory in the step (c), (g) the base station editing a first page in accordance with a capacity at which the client terminal can display data at a time on a display unit thereof, if the data stored in the memory in the step (c) is greater in an amount than the data calculated in the step (e), (h) the base station transmitting the first page to the client terminal, (i) repeating the steps (d) to (f), when the client terminal requests the base station to transmit the client terminal data for next pages, and (j) the base station transmitting the data for next pages to the client terminal, if an excessive load is not exerted on an internet network even if the data for next pages is transmitted to the client terminal at a time.
It is preferable that the method further includes the step of determining the number of pages transmittable to the client terminal at a time, the base station transmitting the pages to the client terminal in the step (j).
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load Dmax per a channel between the base station and the client terminal, (e) the base station calculating an allowable load per a client terminal at the channel, (f) the base station comparing Dk to the number of pages N of a homepage which the client terminal requests to download therein, wherein Dk is defined as follows:
Dk=Dmax/K
wherein K indicates the number of client terminals concurrently making access to a homepage, and (g) the base station transmitting all data of the homepage to the client terminal, if Dk is equal to or greater than N (Dkxe2x89xa7N).
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load Dmax per a channel between the base station and the client terminal, (e) the base station calculating an allowable load per a client terminal at the channel, (f) the base station comparing Dk to the number of pages N of a homepage which the client terminal requests to download therein, wherein Dk is defined as follows:
Dk=Dmax/K
wherein K indicates the number of client terminals concurrently making access to a homepage, and (g) the base station transmitting data of the homepage by every M pages to the client terminal, if Dk is smaller than N, but equal to or greater than N/M (N greater than Dkxe2x89xa7N/M), wherein M is an integer equal to or greater than 2 and smaller than the N.
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load Dmax per a channel between the base station and the client terminal, (e) the base station calculating an allowable load per a client terminal at the channel, (f) the base station comparing Dk to the number of pages N of a homepage which the client terminal requests to download therein, wherein Dk is defined as follows:
Dk=Dmax/K
wherein K indicates the number of client terminals concurrently making access to a homepage, and (g) the base station transmitting data of the homepage by every L pages to the client terminal, if Dk is smaller than N/M, but equal to or greater than 1 (N/M greater than Dkxe2x89xa71), wherein M is an integer equal to or greater than 2 and smaller than the N, and L indicates an integer smaller than the M.
There is further provided a method of downloading data to a client terminal in a radio network communication system including at least one server, at least one client terminal and at least one base station, including the steps of (a) a user of the client terminal making a request to access to a homepage, (b) the server transmitting data to the base station in accordance with the request, (c) the base station storing the data in a memory, (d) the base station calculating a network load Dmax per a channel between the base station and the client terminal, (e) the base station calculating an allowable load per a client terminal at the channel, (f) the base station comparing Dk to the number of pages N of a homepage which the client terminal requests to download therein, wherein Dk is defined as follows:
Dk=Dmax/K
wherein K indicates the number of client terminals concurrently making access to a homepage, and (g) the base station transmitting data of the homepage by every one page to the client terminal, if Dk is smaller than 1.